Harbor Watch, the water-quality monitoring program at Earthplace in Westport, has received a $25,000 grant from the Fairfield County Community Foundation to put toward expansion of its laboratory.

Harbor Watch hopes to triple the size of its existing lab so it can expand the geographic area in which it tests water, the organization said in a news release. The 26-year-old organization's goal is to reverse the biological decline of Long Island Sound.

The most recent grant brings to $50,000 the amount raised -- about half of the estimated $90,000 to $100,000, Harbor Watch said it needs for the project. The Jeniam Foundation previously donated $25,000 toward the expansion.

With four full-time professionals and volunteer field teams of high school students, the organization now monitors Long Island Sound between Bridgeport and Stamford, plus inland waterways within in that stretch of coastline. A healthier Sound would protect biological diversity, commercial fishery operations and recreational opportunities, according to the release.

Harbor Watch said it hopes construction of the new lab at Earthplace on Woodside Lane can begin early next year. It expects a mix of private and public funding will make up the remaining $40,000 to $50,000 needed.

The agency has taken a first step toward geographic expansion this summer with preliminary testing on Five-Mile River in Norwalk's Rowayton section and Holly Pond between Darien and Stamford, according to Sarah S. Ferrante, the Harbor Watch development and marketing manager.

She said further expansion next year is expected to include rivers and harbors in Darien, Stamford and the Pequonnock River in Bridgeport, Trumbull and Monroe.